package com.day07.ex07;

public class StudentDemo {
    public static void main(String[] args) {
        Student s1=new Student();
        s1.show();
        Student s2=new Student("林青霞");
        s1.show();
        Student s3=new Student(30);
        s1.show();
        Student s4=new Student("林青霞",30);
        s1.show();

    }
}
